Method and apparatus for improving the transmitting and receiving directivity in long-range ultrasonic testing

An apparatus for improving transmission directivity according to an embodiment of the present invention includes a phased array probe including a channel 1 transducer and a channel 2 transducer which are arranged at intervals corresponding to a quarter wavelength at a center frequency of a guided wave pulse for long-range ultrasonic testing, and a drive unit which supplies electric pulses with opposite phases to the channel 1 transducer and the channel 2 transducer of the channel 1 transducer and the channel 2 transducer, which is disposed on the front end on the basis of an intended transmission direction, is driven with delay by a time corresponding to a quarter frequency of the center frequency than the other transducer disposed on the rear end.